One step production of in situ nitrogen doped mesoporous carbon confined sulfur for lithium–sulfur batteries

Abstract

Nitrogen doped mesoporous carbon (NMC) with high specific surface area, large pore volume and stable nitrogen content has been prepared by in situ doping through one step carbonization to immobilize sulfur for lithium–sulfur batteries. The structure and composition of the prepared NMC and NMC@S composites are confirmed with nitrogen sorption, elemental analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction patterns (XRD), high resolution transmission electron microscopy (HR-TEM) and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) images show a homogeneous distribution of sulfur within NMC@S. In comparison with free doped mesoporous carbon (MC), the NMC@S with high sulfur content (65%) is found to exhibit a higher initial discharge capacity of 1012 mA h g⁻¹ and higher capacity retention. The electrochemical performance of Li–S batteries is improved by the nitrogen doping, which not only enhances the electric conductivity but also further confines polysufides to the mesoporous carbon from shuttle effect.